Thousands of Palestinians in the West Bank flocked on Friday to a Hamas rally in Hebron, the first such rally that Hamas’s rival Fatah faction, which controls the West Bank, had permitted in years. Waving Hamas banners and carrying fake missiles on their shoulders, the demonstrators subsequently marched toward an Israeli checkpoint and attacked Israeli soldiers with rocks. Hamas’s growing strength in the West Bank raises the specter that the Iran-backed terror group may be able to supplant Fatah rule in the territory, essentially replicating its violent 2007 expulsion of Fatah from the Gaza Strip. The possibility will deeply complicate diplomacy aimed at urging Jerusalem to cede territory to a Fatah-led West Bank government.